My German Shepherd is almost one. On the whole she's a great dog but can be reactive to other dogs in that she will growl if they run up to her and bark at them if they persist. She is neutral to other dogs if they don't approach and actively friendly to dogs she knows. She has had loads of training and it's on going.
Most owners are sensible and put their dogs on a lead when they see her on a lead but some idiots don't or can't. What do you do in these situations? Should she be muzzled? I don't want to just do road walks to avoid off lead dogs but would also hate her to hurt another dog.